1. Field of the Invention
The present invention relates to a state detection device for power supply system that detects the state of a power storage means in a power supply system that uses the power storage means such as a lithium secondary battery, a nickel-metal hydride battery, a lead battery, an electrical double layer capacitor, or the like.
2. Description of Related Art
Power supply systems, distributed electric power storage devices and electric vehicles that use power storage means such as batteries are provided with a state detection device, which detects the state of the power storage means, for a safe, effective use of the power storage means. The states of the power storage means include the state of charge (SOC), which indicates how much the power storage means is charged or how much the dischargeable charge amount remains, the state of health (SOH), which indicates how much the power storage means is deteriorated, and so on.
In order to detect the state of the power storage means, the state detection device stores property information (internal DC resistance and the like) of the power storage means in advance, and executes processing to obtain the SOC, the SOH, or the like based upon the information. However, since the properties of the power storage means vary individually and change with deterioration, the property information needs to be optimized to fit the power storage means so as to perform battery state detection with a high degree of accuracy.
There is a known state detection device for power supply system that solves the problem by monitoring state detection results of the battery, detecting the state as a conflict deviating from the theoretical value in the event that the result exceeds a predetermined threshold, and correcting the property information in response to the detected conflict (patent reference literature 1).
[Patent Reference Literature 1] Japanese Laid Open Patent Publication No. 2006-242880
Detection of a conflict in a state detection result and correction to property information allow the property information to be optimized according to individual variability of the power storage means and the current deterioration development, thereby achieving high accuracy in battery state detection. The achievement of high-frequency correction to the property information enables the property information optimized for the power storage means to be obtained in a short time. In particular, in the event that there is a difference between the actual property information of the power storage means and that managed by the state detection device, it is preferable to correct the property information on the state detection device side with a high frequency so as to optimize the same as fast as possible. The present invention intends to provide a state detection device for power supply system that, if there is any conflict deviating from the theoretical value which arises in the result of the state detection of the power storage means, detects the conflict and corrects with a high frequency the property information necessary for state detection.